Sodium Guidelines 'Need to Be Rethought,' Experts Say

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People whose diets contain moderate levels of sodium may have
healthier hearts and live longer than those who consume too much
or too little of the mineral, new research suggests.

In a large international study, researchers found that men and
women who ate between 3,000 and 6,000 milligrams of sodium per
day had a lower risk of
major cardiovascular problems, such as heart attack, stroke
or heart failure, and they also had a lower risk of dying over a
four-year period compared with people who consumed more, or less,
sodium.

After following participants for nearly four years, the analysis
found that people who consumed more than 6,000 mg of sodium
daily, as well as those who consumed less than 3,000 mg daily,
had a higher risk of dying from any cause, and from heart-related
causes during the study, and were more likely to have heart
problems.

"Our study looked at
optimal levels of sodium around the world, and we found that
being in the middle is the safest amount for optimal health,"
said study author Andrew Mente, an associate professor of
clinical epidemiology and biostatistics at McMaster University in
Ontario, Canada.

On average, U.S. adults consume 3,400 mg of sodium daily.

However, current federal dietary guidelines encourage Americans
to reduce sodium intake: They recommend that most people
ages 14 to 50 limit their sodium intake to 2,300 mg daily, and
advise people ages 51 and older, as well as groups at high risk
of heart disease (including African Americans, and adults with
high blood pressure, diabetes or kidney disease) to cut back to
1,500 mg daily. [ 13
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"The findings indicate that current sodium guidelines need to be
rethought," Mente said. The study was important because it
was large, and looked at the long-term effects of sodium on
actual clinical events, he said.

The results also showed that very few people — only 4 percent —
had sodium intakes that fell within the U.S. guidelines.

Rethinking sodium

For the study, the researchers evaluated nearly 102,000 people
ages 35 to 70 in 17 countries, ranging from wealthy nations to
low-income countries. Most participants had no history of heart
disease, so the sample represented the general population rather
people at high-risk of heart disease, the researchers said in
their report, published online today (Aug. 13) in The New England
Journal of Medicine.

Each participant provided one sample of morning urine, which the
researchers used to estimate their 24-hour sodium and potassium
excretion levels, which are considered a reliable measure of
dietary intake for these two nutrients.

Although having too much
salt in the diet receives more attention, there's evidence to
suggest there may also be health consequences from getting too
little of it.

Other recent studies have also found a link between diets low in
sodium and an increased risk of death and heart problems. Further
research is needed to explain why an increased health risk is
seen when sodium levels fall, Mente said.

The data also showed that people whose diets contained more than
1,500 milligrams of potassium per day were less likely to die
during the study or have heart disease compared with those
getting less potassium.

Potassium minimizes the impact of sodium on blood pressure, Mente
said, but he suspects that
higher potassium intakes could also be a marker of a
generally healthier diet, because fruits and vegetables are rich
in potassium.

As for the practical implications of the research, Mente said
that if people are eating large amounts sodium (more than 6,000
mg of sodium daily) or have high blood pressure, it still makes
sense to limit salt by using less in cooking and at meals, as
well as to cut back on processed foods, such as cured meats,
canned soups and sauces.

But people who consume sodium in moderation (between 3,000 and
6,000 mg) might not need to lower their intake, and doing so may
even increase heart disease risk, Mente said.

A large clinical trial is needed to compare the health effects of
a group on a low-sodium diet to people following their usual
diets.

In the meantime, "For a
healthier heart and to live longer, rather than focusing on a
single nutrient, such as restricting sodium intake, it's more
important to follow a healthy diet, get regular exercise and not
smoke," Mente said.